diff --git a/README.md b/README.md
index 1d2dd7c..98e8689 100644
--- a/README.md
+++ b/README.md
@@ -14,6 +14,7 @@ Go client for Pilosa high performance distributed bitmap index.
 
 * **v0.3.2**:
     * Updated the accepted values for index, frame names and labels to match with the Pilosa server.
+    * `Union` query now accepts zero or more variadic arguments. `Intersect` and `Difference` queries now accept one or more variadic arguments.
 
 * **v0.3.1** (2017-05-01):
     * Initial version
@@ -163,9 +164,9 @@ Please check [Pilosa documentation](https://www.pilosa.com/docs) for PQL details
 
 Index:
 
-* `Union(bitmap1 *PQLBitmapQuery, bitmap2 *PQLBitmapQuery, ...) *PQLBitmapQuery`
-* `Intersect(bitmap1 *PQLBitmapQuery, bitmap2 *PQLBitmapQuery, ...) *PQLBitmapQuery`
-* `Difference(bitmap1 *PQLBitmapQuery, bitmap2 *PQLBitmapQuery, ...) *PQLBitmapQuery`
+* `Union(bitmaps *PQLBitmapQuery...) *PQLBitmapQuery`
+* `Intersect(bitmaps *PQLBitmapQuery...) *PQLBitmapQuery`
+* `Difference(bitmaps *PQLBitmapQuery...) *PQLBitmapQuery`
 * `Count(bitmap *PQLBitmapQuery) *PQLBaseQuery`
 * `SetColumnAttrs(columnID uint64, attrs map[string]interface{}) *PQLBaseQuery`
 
diff --git a/orm.go b/orm.go
index ebeef20..ef62ec7 100644
--- a/orm.go
+++ b/orm.go
@@ -239,20 +239,26 @@ func (d *Index) RawQuery(query string) *PQLBaseQuery {
 
 // Union creates a Union query.
 // Union performs a logical OR on the results of each BITMAP_CALL query passed to it.
-func (d *Index) Union(bitmap1 *PQLBitmapQuery, bitmap2 *PQLBitmapQuery, bitmaps ...*PQLBitmapQuery) *PQLBitmapQuery {
-	return d.bitmapOperation("Union", bitmap1, bitmap2, bitmaps...)
+func (d *Index) Union(bitmaps ...*PQLBitmapQuery) *PQLBitmapQuery {
+	return d.bitmapOperation("Union", bitmaps...)
 }
 
 // Intersect creates an Intersect query.
 // Intersect performs a logical AND on the results of each BITMAP_CALL query passed to it.
-func (d *Index) Intersect(bitmap1 *PQLBitmapQuery, bitmap2 *PQLBitmapQuery, bitmaps ...*PQLBitmapQuery) *PQLBitmapQuery {
-	return d.bitmapOperation("Intersect", bitmap1, bitmap2, bitmaps...)
+func (d *Index) Intersect(bitmaps ...*PQLBitmapQuery) *PQLBitmapQuery {
+	if len(bitmaps) < 1 {
+		return NewPQLBitmapQuery("", d, NewError("Intersect operation requires at least 1 bitmap"))
+	}
+	return d.bitmapOperation("Intersect", bitmaps...)
 }
 
 // Difference creates an Intersect query.
 // Difference returns all of the bits from the first BITMAP_CALL argument passed to it, without the bits from each subsequent BITMAP_CALL.
-func (d *Index) Difference(bitmap1 *PQLBitmapQuery, bitmap2 *PQLBitmapQuery, bitmaps ...*PQLBitmapQuery) *PQLBitmapQuery {
-	return d.bitmapOperation("Difference", bitmap1, bitmap2, bitmaps...)
+func (d *Index) Difference(bitmaps ...*PQLBitmapQuery) *PQLBitmapQuery {
+	if len(bitmaps) < 1 {
+		return NewPQLBitmapQuery("", d, NewError("Difference operation requires at least 1 bitmap"))
+	}
+	return d.bitmapOperation("Difference", bitmaps...)
 }
 
 // Count creates a Count query.
@@ -273,16 +279,9 @@ func (d *Index) SetColumnAttrs(columnID uint64, attrs map[string]interface{}) *P
 		d.options.ColumnLabel, columnID, attrsString), d, nil)
 }
 
-func (d *Index) bitmapOperation(name string, bitmap1 *PQLBitmapQuery, bitmap2 *PQLBitmapQuery, bitmaps ...*PQLBitmapQuery) *PQLBitmapQuery {
+func (d *Index) bitmapOperation(name string, bitmaps ...*PQLBitmapQuery) *PQLBitmapQuery {
 	var err error
-	if err = bitmap1.Error(); err != nil {
-		return NewPQLBitmapQuery("", d, err)
-	}
-	if err = bitmap2.Error(); err != nil {
-		return NewPQLBitmapQuery("", d, err)
-	}
-	args := make([]string, 0, 2+len(bitmaps))
-	args = append(args, bitmap1.serialize(), bitmap2.serialize())
+	args := make([]string, 0, len(bitmaps))
 	for _, bitmap := range bitmaps {
 		if err = bitmap.Error(); err != nil {
 			return NewPQLBitmapQuery("", d, err)
diff --git a/orm_test.go b/orm_test.go
index 458bd1d..5189faf 100644
--- a/orm_test.go
+++ b/orm_test.go
@@ -132,6 +132,12 @@ func TestUnion(t *testing.T) {
 	comparePQL(t,
 		"Union(Bitmap(rowID=10, frame='sample-frame'), Bitmap(project=2, frame='collaboration'))",
 		sampleIndex.Union(b1, b4))
+	comparePQL(t,
+		"Union(Bitmap(rowID=10, frame='sample-frame'))",
+		sampleIndex.Union(b1))
+	comparePQL(t,
+		"Union()",
+		sampleIndex.Union())
 }
 
 func TestIntersect(t *testing.T) {
@@ -144,6 +150,9 @@ func TestIntersect(t *testing.T) {
 	comparePQL(t,
 		"Intersect(Bitmap(rowID=10, frame='sample-frame'), Bitmap(project=2, frame='collaboration'))",
 		sampleIndex.Intersect(b1, b4))
+	comparePQL(t,
+		"Intersect(Bitmap(rowID=10, frame='sample-frame'))",
+		sampleIndex.Intersect(b1))
 }
 
 func TestDifference(t *testing.T) {
@@ -156,6 +165,9 @@ func TestDifference(t *testing.T) {
 	comparePQL(t,
 		"Difference(Bitmap(rowID=10, frame='sample-frame'), Bitmap(project=2, frame='collaboration'))",
 		sampleIndex.Difference(b1, b4))
+	comparePQL(t,
+		"Difference(Bitmap(rowID=10, frame='sample-frame'))",
+		sampleIndex.Difference(b1))
 }
 
 func TestTopN(t *testing.T) {
@@ -201,6 +213,16 @@ func TestBitmapOperationInvalidArg(t *testing.T) {
 	if q.Error() == nil {
 		t.Fatalf("should have failed")
 	}
+	// not enough bitmaps supplied
+	q = sampleIndex.Difference()
+	if q.Error() == nil {
+		t.Fatalf("should have failed")
+	}
+	// not enough bitmaps supplied
+	q = sampleIndex.Intersect()
+	if q.Error() == nil {
+		t.Fatalf("should have failed")
+	}
 }
 
 func TestSetColumnAttrsTest(t *testing.T) {